Everybody dies of something

I recently wrote a blog post criticizing how evolution was used in very peculiar way. In an opinion piece, two Swedish academics claimed that we should eat the kind of diet that our bodies “were adapted to” – said to be the time when our distant relatives were hunters and gatherers. When I stated that we’ve never been perfectly adapted, I noticed a level of opposition I hadn't experienced before. Some comments were reasonable while others were just plain silly, along the lines of “you’re just a biased vegan, dude”. If I was a vegan I might have been offended.

It’s clear that anything involving diet can provoke quite a stir. And some of the people devoted to a paleo or LCHF diet are – frankly – quite obsessed. The thing is though, I wasn’t even writing about food in my blog post, but rather about evolution. That's what Marlene Zuk has done, much more comprehensively, in her book Paleofantasy (2013). Knowing the basic scientific facts about evolution can help us avoid some of the bogus claims made about diets, gender roles and disease.

Marlene Zuk is a professor of ecology, evolution, and behavior at the University of Minnesota in the US. When I first read about her work it had nothing to do with diet, but was all about crickets and evolution in the fast lane. She had been studying field crickets in Hawaii for two decades by then, and discovered that a new kind of male cricket evolved in just a few years. This background in empirical science provides her with a solid foundation to build from when she approached the paleofantasies popping up in such various fields as diet, disease, exercise, and gender roles. It’s a joy to read what she writes about recent major discoveries in evolutionary biology, but her arguments are essentially variations on the same theme: no, humans are and were never perfectly adapted to a Stone Age environment. Or as she puts it, all living organisms are “both always facing new environments, and always shackled by genes from the past".

Organisms such as humans are responding to a continually changing environment and hence evolution itself is continual too. Yes, some genes involved in human disease are shared with bacteria making them more than 2 billion years old. Other gene variants, like the one making some of us tolerant to lactose as grown-ups, evolved only 7000 years ago (to be lactose intolerant as an adult is the original state) – we have never been in perfect harmony with our environment.

This is not a book about diet, nor does Marlene Zuk give lifestyle advice on how to avoid getting sick – although she does say that it is most probably good to get off the couch. Rather, it’s about the misconception that humans have stopped evolving, and that we should live in a way that resembles some poorly defined period in distant human history. Nature has not singled out humans for special treatment; we’re not the “most recently evolved species on the planet”. Making up stories based on Stone Age preconceptions does not help at all.